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    <title>Document</title>
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<script>
    //    function zhuanhuan(arg) {
    //     //将字符串转换成数组
    //     var str=arg.split('');
    //     for(var i = 0; i < str.length; i++) {
    //         //用字符的ASCII编码区分大小写
    //         if (str[i].charCodeAt() >= 65 && str[i].charCodeAt() <= 90) {
    //             str[i] = str[i].toLowerCase();
    //         } else {
    //             str[i] = str[i].toUpperCase();
    //         }
    //     }
    //     return str.join('');
    //    }
    //    console.log(zhuanhuan('heLlO WorLD'))


</script>